—Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him) commented:

“The outward sense is that he was encamped in a tent while travelling: he delayed Dhuhr, then came out and performed Dhuhr and ʿAsr together; he then went back inside, came out once more, and performed Maghrib and ʿIshaʾ together. Going in and out takes place only when one is settled, whereas for someone who is actually on the move one would say that he dismounted and mounted, not that he entered and exited …

This proves that the Prophet ﷺ at times combined the prayers while travelling and at times did not, and the latter was what he did most frequently on his journeys. It also makes clear that combining is not an inherent sunnah of travel in the way that shortening is; rather, it is done when there is a need, whether one is travelling or resident, for he also combined while resident so as not to burden his community. Therefore, whenever the traveller needs to combine, he should do so—whether because he will be moving during the time of the second prayer, or during the time of the first and stopping would be difficult, or even when he is already encamped but has some other need. For example, he may need to sleep and rest at the times of Dhuhr and ʿIshaʾ: he stops at Dhuhr exhausted, having stayed up late, hungry and in need of rest, food, and sleep, so he postpones Dhuhr until the time of ʿAsr, and then finds it necessary to bring ʿIshaʾ forward with Maghrib and sleep afterward…"